The Chinese railroad system is not private. It isn't even a state owned company. It's the "Ministry of Railroads". There's nothing private about it; it takes taxpayer money and in return subsidizes rail travel. The Ministry of Railroads is a very powerful government department. It operates its own police, telecom company and supply chain. It has the power to silence opponents (like when it ordered the propaganda department to silence criticism of the crash, but the State Administration of Radio and TV blocked it) and is the classic bloated, corrupt bureaucracy. It's not called "Big Rail" 铁老大 in China for nothing.
Actually, the revenue of the top 60 state owned companies in China is something like 45% of GDP. Somewhere in fortune 500 they said this.